Various kinds of shift control devices are known. They perform upshift and downshift controls of gear positions of an automatic transmission, on the basis of vehicle speeds and engine loads (throttle opening or accelerator opening) as parameters, according to upshift and downshift lines which set upshift and downshift transmission patterns per gear position. Such shift control devices, for example one described in Patent Document 1, conventionally prevent shift hunting (shift-busy state) that a vehicle re-downshifts or re-upshifts immediately after upshift or downshift.
The above-described shift control devices are adapted to, when a kickdown occurs, shift an upshift line on a shift map to a low throttle opening (a low accelerator opening) and high vehicle speed side, expanding a hysteresis range for upshift and downshift. In this hysteresis range, an allowance driving force which could occur at a shift position after upshift is constantly calculated. And only when this allowance driving force exceeds a predetermined value, the devices are adapted to permit an upshift, or in other words, cancel a shift hold. Also, when the allowance driving force falls on a lower throttle opening (a lower accelerator opening) and higher vehicle speed side than the above-mentioned shifted upshift line, an upshift is permitted, in case of a re-stepping of an accelerator pedal, after a delay time which is a predetermined constant time or a time set based on a variation of vehicle speed and throttle opening passes.